fix: breakpoints in JS not working

packages/vite/rollup.config.ts

@@ -195,7 +195,7 @@ function createCjsConfig(isProduction: boolean) {
       ...Object.keys(pkg.dependencies),
       ...(isProduction ? [] : Object.keys(pkg.devDependencies)),
     ],
-    plugins: [...createNodePlugins(false, false, false), bundleSizeLimit(123)],
+    plugins: [...createNodePlugins(false, false, false), bundleSizeLimit(155)],
   })
 }
 

packages/vite/src/node/server/index.ts

@@ -235,7 +235,7 @@ export interface ViteDevServer {
    */
   ssrTransform(
     code: string,
-    inMap: SourceMap | null,
+    inMap: SourceMap | { mappings: '' } | null,
     url: string,
     originalCode?: string,
   ): Promise<TransformResult | null>
@@ -385,7 +385,7 @@ export async function _createServer(
     resolvedUrls: null, // will be set on listen
     ssrTransform(
       code: string,
-      inMap: SourceMap | null,
+      inMap: SourceMap | { mappings: '' } | null,
       url: string,
       originalCode = code,
     ) {

packages/vite/src/node/server/middlewares/indexHtml.ts

@@ -282,7 +282,7 @@ const devHtmlHook: IndexHtmlTransformHook = async (
       const result = await server!.pluginContainer.transform(code, mod.id!)
       let content = ''
       if (result) {
-        if (result.map) {
+        if (result.map && 'version' in result.map) {
           if (result.map.mappings) {
             await injectSourcesContent(
               result.map,

packages/vite/src/node/server/pluginContainer.ts

@@ -132,7 +132,7 @@ export interface PluginContainer {
       inMap?: SourceDescription['map']
       ssr?: boolean
     },
-  ): Promise<{ code: string; map: SourceMap | null }>
+  ): Promise<{ code: string; map: SourceMap | { mappings: '' } | null }>
   load(
     id: string,
     options?: {
@@ -481,7 +481,7 @@ export async function createPluginContainer(
         typeof err.loc?.column === 'number'
       ) {
         const rawSourceMap = ctx._getCombinedSourcemap()
-        if (rawSourceMap) {
+        if (rawSourceMap && 'version' in rawSourceMap) {
           const traced = new TraceMap(rawSourceMap as any)
           const { source, line, column } = originalPositionFor(traced, {
             line: Number(err.loc.line),
@@ -525,7 +525,7 @@ export async function createPluginContainer(
     originalCode: string
     originalSourcemap: SourceMap | null = null
     sourcemapChain: NonNullable<SourceDescription['map']>[] = []
-    combinedMap: SourceMap | null = null
+    combinedMap: SourceMap | { mappings: '' } | null = null
 
     constructor(filename: string, code: string, inMap?: SourceMap | string) {
       super()
@@ -540,7 +540,7 @@ export async function createPluginContainer(
       }
     }
 
-    _getCombinedSourcemap(createIfNull = false) {
+    _getCombinedSourcemap() {
       if (
         debugSourcemapCombine &&
         debugSourcemapCombineFilter &&
@@ -553,12 +553,26 @@ export async function createPluginContainer(
       }
 
       let combinedMap = this.combinedMap
+      // { mappings: '' }
+      if (
+        combinedMap &&
+        !('version' in combinedMap) &&
+        combinedMap.mappings === ''
+      ) {
+        this.sourcemapChain.length = 0
+        return combinedMap
+      }
+
       for (let m of this.sourcemapChain) {
         if (typeof m === 'string') m = JSON.parse(m)
         if (!('version' in (m as SourceMap))) {
+          // { mappings: '' }
+          if ((m as SourceMap).mappings === '') {
+            combinedMap = { mappings: '' }
+            break
+          }
           // empty, nullified source map
-          combinedMap = this.combinedMap = null
-          this.sourcemapChain.length = 0
+          combinedMap = null
           break
         }
         if (!combinedMap) {
@@ -570,15 +584,6 @@ export async function createPluginContainer(
           ]) as SourceMap
         }
       }
-      if (!combinedMap) {
-        return createIfNull
-          ? new MagicString(this.originalCode).generateMap({
-              includeContent: true,
-              hires: 'boundary',
-              source: cleanUrl(this.filename),
-            })
-          : null
-      }
       if (combinedMap !== this.combinedMap) {
         this.combinedMap = combinedMap
         this.sourcemapChain.length = 0
@@ -587,7 +592,15 @@ export async function createPluginContainer(
     }
 
     getCombinedSourcemap() {
-      return this._getCombinedSourcemap(true) as SourceMap
+      const map = this._getCombinedSourcemap()
+      if (!map || (!('version' in map) && map.mappings === '')) {
+        return new MagicString(this.originalCode).generateMap({
+          includeContent: true,
+          hires: 'boundary',
+          source: cleanUrl(this.filename),
+        })
+      }
+      return map
     }
   }
 

packages/vite/src/node/server/send.ts

@@ -5,6 +5,8 @@ import type {
 } from 'node:http'
 import getEtag from 'etag'
 import type { SourceMap } from 'rollup'
+import MagicString from 'magic-string'
+import { removeTimestampQuery } from '../utils'
 import { getCodeWithSourcemap } from './sourcemap'
 
 const alias: Record<string, string | undefined> = {
@@ -18,7 +20,7 @@ export interface SendOptions {
   etag?: string
   cacheControl?: string
   headers?: OutgoingHttpHeaders
-  map?: SourceMap | null
+  map?: SourceMap | { mappings: '' } | null
 }
 
 export function send(
@@ -56,10 +58,20 @@ export function send(
   }
 
   // inject source map reference
-  if (map && map.mappings) {
+  if (map && 'version' in map && map.mappings) {
     if (type === 'js' || type === 'css') {
       content = getCodeWithSourcemap(type, content.toString(), map)
     }
+  } else {
+    if (type === 'js' && (!map || map.mappings !== '')) {
+      const urlWithoutTimestamp = removeTimestampQuery(req.url!)
+      const ms = new MagicString(content.toString())
+      content = getCodeWithSourcemap(
+        type,
+        content.toString(),
+        ms.generateMap({ source: urlWithoutTimestamp, hires: 'boundary' }),
+      )
+    }
   }
 
   res.statusCode = 200

packages/vite/src/node/server/transformRequest.ts

@@ -31,7 +31,7 @@ const debugCache = createDebugger('vite:cache')
 
 export interface TransformResult {
   code: string
-  map: SourceMap | null
+  map: SourceMap | { mappings: '' } | null
   etag?: string
   deps?: string[]
   dynamicDeps?: string[]
@@ -286,15 +286,23 @@ async function loadAndTransform(
     map = transformResult.map
   }
 
-  if (map && mod.file) {
-    map = (typeof map === 'string' ? JSON.parse(map) : map) as SourceMap
-    if (map.mappings) {
-      await injectSourcesContent(map, mod.file, logger)
+  let normalizedMap: SourceMap | { mappings: '' } | null
+  if (typeof map === 'string') {
+    normalizedMap = JSON.parse(map)
+  } else if (map) {
+    normalizedMap = map as SourceMap | { mappings: '' }
+  } else {
+    normalizedMap = null
+  }
+
+  if (normalizedMap && 'version' in normalizedMap && mod.file) {
+    if (normalizedMap.mappings) {
+      await injectSourcesContent(normalizedMap, mod.file, logger)
     }
 
     const sourcemapPath = `${mod.file}.map`
     applySourcemapIgnoreList(
-      map,
+      normalizedMap,
       sourcemapPath,
       config.server.sourcemapIgnoreList,
       logger,
@@ -303,16 +311,16 @@ async function loadAndTransform(
     if (path.isAbsolute(mod.file)) {
       for (
         let sourcesIndex = 0;
-        sourcesIndex < map.sources.length;
+        sourcesIndex < normalizedMap.sources.length;
         ++sourcesIndex
       ) {
-        const sourcePath = map.sources[sourcesIndex]
+        const sourcePath = normalizedMap.sources[sourcesIndex]
         if (sourcePath) {
           // Rewrite sources to relative paths to give debuggers the chance
           // to resolve and display them in a meaningful way (rather than
           // with absolute paths).
           if (path.isAbsolute(sourcePath)) {
-            map.sources[sourcesIndex] = path.relative(
+            normalizedMap.sources[sourcesIndex] = path.relative(
               path.dirname(mod.file),
               sourcePath,
             )
@@ -326,12 +334,12 @@ async function loadAndTransform(
 
   const result =
     ssr && !server.config.experimental.skipSsrTransform
-      ? await server.ssrTransform(code, map as SourceMap, url, originalCode)
+      ? await server.ssrTransform(code, normalizedMap, url, originalCode)
       : ({
           code,
-          map,
+          map: normalizedMap,
           etag: getEtag(code, { weak: true }),
-        } as TransformResult)
+        } satisfies TransformResult)
 
   // Only cache the result if the module wasn't invalidated while it was
   // being processed, so it is re-processed next time if it is stale

packages/vite/src/node/ssr/ssrModuleLoader.ts

@@ -202,7 +202,7 @@ async function instantiateModule(
   }
 
   let sourceMapSuffix = ''
-  if (result.map) {
+  if (result.map && 'version' in result.map) {
     const moduleSourceMap = Object.assign({}, result.map, {
       // currently we need to offset the line
       // https://github.com/nodejs/node/issues/43047#issuecomment-1180632750

packages/vite/src/node/ssr/ssrTransform.ts

@@ -38,7 +38,7 @@ const hashbangRE = /^#!.*\n/
 
 export async function ssrTransform(
   code: string,
-  inMap: SourceMap | null,
+  inMap: SourceMap | { mappings: '' } | null,
   url: string,
   originalCode: string,
   options?: TransformOptions,
@@ -51,7 +51,7 @@ export async function ssrTransform(
 
 async function ssrTransformJSON(
   code: string,
-  inMap: SourceMap | null,
+  inMap: SourceMap | { mappings: '' } | null,
 ): Promise<TransformResult> {
   return {
     code: code.replace('export default', `${ssrModuleExportsKey}.default =`),
@@ -63,7 +63,7 @@ async function ssrTransformJSON(
 
 async function ssrTransformScript(
   code: string,
-  inMap: SourceMap | null,
+  inMap: SourceMap | { mappings: '' } | null,
   url: string,
   originalCode: string,
 ): Promise<TransformResult | null> {
@@ -275,7 +275,12 @@ async function ssrTransformScript(
   })
 
   let map = s.generateMap({ hires: 'boundary' })
-  if (inMap && inMap.mappings && inMap.sources.length > 0) {
+  if (
+    inMap &&
+    inMap.mappings &&
+    'sources' in inMap &&
+    inMap.sources.length > 0
+  ) {
     map = combineSourcemaps(url, [
       {
         ...map,

playground/css-sourcemap/__tests__/css-sourcemap.spec.ts

@@ -82,8 +82,7 @@ describe.runIf(isServe)('serve', () => {
         new URL('./linked-with-import.css', page.url()).href,
       )
       const content = await res.text()
-      const lines = content.trim().split('\n')
-      expect(lines[lines.length - 1]).not.toMatch(/^\/\/#/)
+      expect(content).not.toMatch('//#s*sourceMappingURL')
     },
   )
 

playground/js-sourcemap/__tests__/js-sourcemap.spec.ts

@@ -13,8 +13,16 @@ if (!isBuild) {
   test('js', async () => {
     const res = await page.request.get(new URL('./foo.js', page.url()).href)
     const js = await res.text()
-    const lines = js.split('\n')
-    expect(lines[lines.length - 1].includes('//')).toBe(false) // expect no sourcemap
+    const map = extractSourcemap(js)
+    expect(formatSourcemapForSnapshot(map)).toMatchInlineSnapshot(`
+      {
+        "mappings": "AAAA,MAAM,CAAC,KAAK,CAAC,GAAG,CAAC,CAAC,CAAC,CAAC,GAAG,CAAC;",
+        "sources": [
+          "/foo.js",
+        ],
+        "version": 3,
+      }
+    `)
   })
 
   test('ts', async () => {